1. Field of the Invention
The present invention relates to air-driven vehicles and more particularly pertains to pneumatic system for propelling a compressed airdriven vehicle which utilizes a first source of compressed air to operate a first actuating cylinder operable to propel the vehicle and which utilizes the exhaust air from the first actuating cylinder as a source of compressed air to operate a second actuating cylinder which supplements the driving force of the first actuating cylinder.
2. Description of the Prior Art
In the field of air driven vehicles, it has been the general practice to employ a source of compressed air to operate an air actuating cylinder which through its operation propels the vehicle. Such devices have generally proven to be unsatisfactory in operation due to the gross inefficiency associated therewith. Specifically, the tremendous weight involved in the construction of these vehicles, as well as the large amount of compressed air required to propel these vehicles even for a short distance, has made the construction of the same an impractical matter. Many of the problems associated with air vehicle construction have revolved around the fact that a tremendous amount of compressed air is necessary for each rotation of a drive shaft, and as such, those concerned with the development of air-driven vehicles have long recognized the need for either decreasing the amount of compressed air required for any single revolution of a drive shaft or, in the alternative, making more efficient use of the amount of compressed air being employed.
Accordingly, the development of air-driven vehicles has been a slow process and to date, these vehicles have not been regularly employed as a means of transportation, although they apparently were conceived as far back as in the late 19th century. For example, U.S. Pat. No. 331,276, issued Dec. 1, 1885, to Buell, discloses a tricycle having an engine operable by compressed air attached thereto so as to provide a propelling force to the tricycle. In this respect, cylinders of compressed air were illustrated as being operably connected to cranks associated with the tricycle axle by means of air actuated cylinders. However, no mention of, or provision for, a further use of the actuating air being exhausted from the actuating cylinders is made. Similarly, U.S. Pat. No. 589,710, issued Sept. 7, 1897, to Flucks, discloses the use of compressed air or other compressed fluid being conveyed to drive wheels so as to impart movement to a carriage. As with the Buell device, the propelling compressed air is used but one time to impart its driving force and then is exhausted to the atmosphere.
In that the above-discussed compressed air vehicles were totally impractical, a number of attempts have evolved to make more efficient use of the compressed air employed as the driving medium, as well as to provide supplementary propelling forces for use in conjunction with the drive-imparting compressed air. For example, U.S. Pat. No. 3,704,760, issued Dec. 5, 1972, to Maruyama, discloses a propelling system for vehicles utilizing both an air driven motor and an electric motor. the air driven motor is operated by air supplied under pressure from a source of compressed air, such as a cylinder or a liquid-air tank, while the electric motor is driven by a storage battery in which stored electrical energy produced by a generator may assist in the propelling of the vehicle. In this respect, the generator is allegedly driven by a turbine operated by the air supplied under pressure from the source of compressed air, while both the air driven motor and the electric motor are connected to transmission means linked to the driving wheels of the vehicle. In this respect, the Maruyama propelling system utilizes the compressed air to both drive the vehicle and to generate electricity for also driving the vehicle. As can be appreciated, an even greater supply of compressed air would be needed than with a vehicle driven exclusively by compressed air, and accordingly, the problems of vehicle weight and reduction of compressed air requirements are not solved by this construction. Further, no suggestion or teaching is present regarding the use of exhausted compressed air as a source of further energy to propel the vehicle.
U.S. Pat. No. 3,847,058, issued Nov. 12, 1974, to Manor, is even more representative of the many futile attempts to develop an efficient air powered vehicle. In this respect, Manor discloses a vehicle having an air powered engine which utilizes a first reservoir of gaseous fluid under pressure connected to an intake system for operating the engine. A second reservoir is connected to an exhaust system for receiving the spent air, and a suspension-type compressor is operatively connected between a wheel and the chassis whereby relative vertical motion between the wheel and the chassis will cause operation of the compressor. Further, additional compressors are operated primarily from air flow induced by forward motion of the vehicle, and the air from all of the aforementioned compressors is then redirected through the system to again power the vehicle. In effect, the vehicle described therein is exceedingly complex and is apparently directed toward a vehicle which would effectively power itself. At the same time, the exhaust air from the actuating cylinder is not utilized to drive a second separate actuating cylinder, and along the same line of reasoning, the compressed air deliverable to the actuating cylinder is used only one time for imparting a propelling force to the vehicle before it is returned to a storage tank for reuse.
Similarly, U.S. Pat. No. 3,925,984, issued Dec. 16, 1975, to Holleyman, discloses a compressed air power plant for use on a vehicle which utilizes the compressed air to operate actuating cylinders for providing the propelling force necessary to drive the vehicle. The vehicle is further provided with a compressor which is battery operated and which serves to continually supply compressed air to storage tanks so that the vehicle effectively never runs out of compressed air for propulsion, but is limited in its operation only by the extent of the power supplied by the batteries. In other words, once the batteries are expended, the compressor ceases to function and the compressed air supply is exhausted. While this disclosed system may be somewhat practical in nature, it still does not make efficient use of the compressed air utilized, since no means are provided for obtaining energy from the exhausted air.
Along the same line of operation, there is disclosed in U.S. Pat. No. 3,765,180, issued Oct. 16, 1973, to Brown, a compressed air engine used in combination with an auxiliary air compressor for building up the pressure in a compressed air supply tank which feeds air through an engine control valve to the engine pistons. Upon reaching a minimum air pressure, an electric motor is cut off and the auxiliary compressor is simultaneously engaged with the crankshaft to continue to build up air pressure. Also provided is a main recycle air compressor for capturing and reusing exhausted air and supplying the same back to the compressed air supply tank. As can be appreciated, the Brown device relies on a plurality of compressors as part of the system, as well as an electrical supply for driving the same. Again, no mention is to be found of utilizing exhaust air as a compressed air supply for operating a second actuating cylinder. Further, it is readily apparent that vehicles utilizing concurrent supplies of electrical energy are by necessity of a much heavier construction due to the positioning and transporting of batteries, compressors, alternators, etc., thereon.
There has been at least one attempt to devise an operable system for utilizing exhaust air as an independent propulsion medium for operating additional actuating cylinders. In this respect, U.S. Pat. No. 3,666,038, issued May 30, 1972, to Hudspeth et al, discloses a system utilizing a pressure storage vessel for initially charging a first air cylinder of a series of air cylinders. Valve means are disclosed which admits a flow of pressurized air, in a sequential manner, into the cylinders for piston movement thereby to compress spring members to a loaded condition. Additional valve means, closed during downward piston movement, are subsequently actuated to permit dischage of an air impulse by action of the compressed springs combined with a second source of air pressure acting on the other side of the respective pistons. The last cylinder of the series is operable to impart a force to a media for the operation of a motor powering a vehicle. In this connection, only the last cylinder is used to impart a driving force to a vehicle, since the use of the difference size cylinders is strictly for the purpose of increasing pressure, and no use or suggestion is made to save exhaust air at a lower pressure to use again in another larger cylinder to obtain almost the same force each time the air is reused and to have each cylinder used so as to individually impart a driving force to the vehicle.